Some will test the alternator for free in hopes you will buy there. Before that, check the manual that came with the car for all fuse locations to see if there is any big (something over 20A) ones that could have blown. Some bigger fuses are not in that manual so you cop a look at the service manual.
While driving my battery light popped up and after some time, other indidcators started lighting up on the panel and ultimately it stopped. I have tried to charge it externally but it doesn’t last long. Any quick checks to be performed?